unbound 1.5.10 does not build on Solaris

[qutic development]

Hi,

latest unbound 1.5.10 does not build on Solaris. It stops with the following error:

./libtool --tag=CC --mode=compile /opt/gcc-4.8.1/bin/gcc -I. -D_OPENBSD_SOURCE  -I/usr/local/include -std=c99 -flto -D_REENTRANT -pthreads -o unbound-checkconf.lo -c `cat .source`
libtool: compile:  /opt/gcc-4.8.1/bin/gcc -I. -D_OPENBSD_SOURCE -I/usr/local/include -std=c99 -flto -D_REENTRANT -pthreads -c smallapp/unbound-checkconf.c  -fPIC -DPIC -o .libs/unbound-checkconf.o
smallapp/unbound-checkconf.c: In function 'checkconf':
smallapp/unbound-checkconf.c:489:13: error: 'PATH_MAX' undeclared (first use in this function)
  char oldwd[PATH_MAX];
             ^
smallapp/unbound-checkconf.c:489:13: note: each undeclared identifier is reported only once for each function it appears in
*** Error code 1
make: Fatal error: Command failed for target `unbound-checkconf.lo'

The reason is, that limits.h needs to be included on Solaris and Illumos. The following patch fixes it:

https://github.com/jfqd/omnios-build/blob/151014/build/unbound/patches/limits.patch

Would it possible to include it?

- Stefan